In some existing switches, especially switches for high current switching applications damage can be caused by arcing occurring between contacts of the switches when the contacts are opening or closing during operation of the switch. In particular, the energy developed by the arc—which develops between the two contacts (e.g. electrodes) when they transition from a closed position to an open position or from an open to a closed position—degrades the material of the contacts over time and thus reduces the life span of the switch. The arc that develops when the contacts transition from the closed position to the open position (i.e. a break arc) is typically more energetic and more destructive than the arc that develops when the contacts transition from the open position to the closed position (i.e. an open arc).
Also, when these existing switches are used in some high current switching applications, such as vehicle or marine applications, other components of the electrical systems of the vehicle or boat can be detrimentally affected by load dump when the contacts of the switch transition from the closed position to the open position. That is, in this case, for instance, the switch is a battery isolation switch which isolates the battery from an alternator and, when the contacts of the switch transition from the closed position to the open position, the battery being charged is disconnected and components connected to the battery will receive a potentially damaging surge in power.
One existing example of an attempt to minimize load dump in the above mentioned applications and arcing in a switch, and thus minimize damage to the contacts and the components of an electrical system includes using multiple contacts that open and close sequentially at different times to operate the switch. In this example, however, the first contact to make contact and/or the last contact to break will experience the greatest contact wear and eventually will form a high-resistance connection that can cause, for example, excessive heating inside the switch. Another existing example employs auxiliary contacts in addition to the main contacts, which are generally rated for less current than the main contacts, and which are intended to break before main contacts of the switch using an electronic timing circuit. The auxiliary contacts, when breaking before the main contacts, minimize the energy that can be developed by the break arc between the main contacts. In this example, however, the auxiliary contacts can be degraded over time and the electronic timing circuits can fail so as to not ensure the auxiliary contacts are always broken before the main contacts. Also, the electronic delay circuits are generally non-compliant with hazardous/explosive area codes and can be unreliable.